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On Sat, 20 Jun 2009 17:54:04 +0000 (UTC), "Geoffrey S. Mendelson"
wrote: I have a microwave leakage tester. It is calibrated for 2450 mHz, so it should be perfect for testing WiFi Network output power. It is calibrated in mw/cm2 (miliwatts per square centimeter). It is also ham related as I am limited to 100mw EIRP on the 2.4gHz ham band. So I figured that I could use it by measuring the field strength at a specific distance from the antenna, and then applying a conversion factor. See if you can get your money back. I had the same idea a few years ago and purchased a Safeea Inc MD-2000 tester: http://www.allproducts.com/ee/safeea/md-2000.html Of course, the first thing I did was rip it apart: http://802.11junk.com/jeffl/pics/Microwave%20Leakage%20Detector/index.html The diode D1 (labelled C2) is the detector. The apparently random circuit board traces nearby is the "antenna". The sensitivity sucks. I'm only able to get an indication when it's a few cm from the antenna of my access point. Worse, the indication varies radically from zilch to tilt (9.9mw/cm^2). There's no stable indication. At the microwave oven leak test distance of 2 inches, it barely indicates anything, even when I generate continuous traffic with my iPod Touch. If there were some way to generate a CW carrier from the access point, perhaps it might deliver a better and more stable indication. The problem is that the duty cycle of Wi-Fi transmissions are not constant. The MD-2000 microwave leak detector works nicely with the constant duty cycle of the oven controller, but doesn't do as well with the widely varying duty cycle of Wi-Fi. Also, the duty cycle of just the beacon transmissions is very low, resulting in a very low indication. I also have several analog oven leak detectors, which produce similar disgusting results. Topic Drift: Think your microwave oven is well shielded? Put your 2.4GHz cordless phone handset inside the microwave oven. Close the door. Hit the "page" button on the phone base and see if the phone rings. It probably will. So much for shielding. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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